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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Effects of Prepartum Energy and Protein Density on Productivity and Influence of Dietary Iron on Copper Status of Holstein and Jersey Cattle

French, Patrick Douglas 11 April 1999 (has links)
In experiment 1, 24 multiparous Holsteins and 24 multiparous Jerseys were assigned at random to one of four diets containing either 1.25, 1.38, 1.50, or 1.63 Mcal NEL/kg DM to determine the effects of prepartum energy density on productivity. Cows were assigned to diets 28 d before expected calving and received a similar diet 0 to 60 d postpartum. Prepartum DMI increased linearly as dietary energy density increased. Non-esterified fatty acids did not differ for energy density and were greater for Holsteins. Milk and 4% FCM increased linearly as dietary energy density increased, although postpartum DMI was quadratic for energy density. Fat yield increased linearly with energy density and protein yield did not differ. Increasing prepartum diet energy density increased yield of milk and 4% FCM. In experiment 2, 26 multiparous and 18 primiparous Jerseys were assigned to one of two CP and rumen undegradable protein (RUP) concentrations 30 d before expected calving to determine the effects of CP and RUP on productivity. Cows received a similar diet 0 to 60 d postpartum. Prepartum CP concentrations were 12 and 15% and prepartum RUP (% of CP) concentrations were 30 and 45%. Dry matter intake was not affected by CP or RUP. Milk yield and 4% FCM yield did not differ for CP or RUP. In addition, milk protein concentration and yield were similar for CP and RUP. Positive calculated metabolizable protein balance for 12% CP and 30% RUP concentrations may have precluded responses to increasing prepartum CP and RUP. In experiment 3, 12 Holstein and 12 Jersey multiparous cows were assigned at random to diets containing 0 or 500 mg FeCO3/kg DM to investigate the effects of dietary Fe on milk production and Cu status. Hepatic Cu did not differ for breeds or Fe supplementation. For Jerseys, hepatic Fe was greater for cows receiving supplemental Fe. Hepatic Zn was similar for breed and Fe supplementation. Plasma Cu was greater for Jerseys compared to Holsteins and did not differ for Fe supplementation. Plasma Fe and Zn did not differ for breeds or Fe supplementation. Iron supplementation did not affect yield of milk or 4% FCM. Dietary Fe did not affect Cu status of Holstein and Jersey cows in this experiment. / Ph. D.
132

Tests of demountable reinforced concrete slabs

Almahmood, Hanady A.A., Ashour, Ashraf, Figueira, Diogo, Yildirim, Gurkan, Aldemir, A., Sahmaran, M. 24 October 2022 (has links)
Yes / This paper presents an experimental investigation of demountable reinforced concrete slabs using dry connections between reinforced concrete slab elements. The test specimens comprised six full-scale reinforced concrete slabs; one control slab monolithically cast, while the other five slabs were produced with mid-span demountable dry connections. The slab elements were cast separately and assembled using top and bottom steel plates joined to each side of the slab element by high tensile steel bolts with or without a shear key and embedded steel block. Theoretical analysis of the behaviour of the demountable slabs tested in comparison with the control specimen was also conducted. The test results showed that using a dry connection consisting of a shear key at the assembled section is the most effective technique in terms of moment resistance, deflection, and flexural stiffness. On the other hand, the dry connection with embedded steel blocks failed prematurely because of stress concentration at the block edges. The moment capacity and deflection predictions of demountable slabs have reasonably correlated with the experimental results but required additional calibrated data from experiments. / This work was supported by an Institutional Links grant, ID 414633184, under the Newton-Kâtip Çelebi Fund partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and TÜBİTAK – Scientific and Technological Research Council of Turkey and delivered by the British Council. For further information, please visit www.newtonfund.ac.uk.
133

Tool Life and Flank Wear Modeling of Physical Vapour Deposited TiAlN/TiN Multilayer Coated Carbide End Mill Inserts when Machining 4340 Steel Under Dry and Semi-Dry Cutting Conditions

Chakraborty, Pinaki 03 January 2008 (has links)
This study investigates the tool wear of advanced PVD TiALN/TiN multilayer coated end mill inserts when dry and semi-dry machining 4340 low alloy medium carbon steel. A factorial design of experiment setup consisting of two levels of speed, three levels of feed, two levels of depth of cut, and two levels of cutting conditions (semi-dry and dry) was used for the study. The combination of cutting conditions that gave the best response for different components of cutting force, cutting power, surface roughness and tool life were determined using MANOVA & ANOVA analysis and Tukey comparison of means test using MINITAB statistical software package. From a study of the Energy Dispersive X ray (EDX) analysis and primary back scatter images obtained from the worn out crater surface of the insert, it was observed that diffusion wear prevailed under both dry and semi-dry machining conditions. A tool life model was developed using multiple regression analysis within the range of cutting conditions selected. A model for flank wear progression was also developed using mixed effects modeling technique using S Plus statistical software package. This technique takes into account between and within work piece variations during end milling and produces a very accurate model for tool wear progression. This is the first time application of the mixed effects modeling technique in metal cutting literature.
134

Environmental impact assessment (water pollution) of a floating dock in Yam O /

Cho, Tat-wing, Asam. January 1997 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 66-72).
135

Fashioning a greener shade of clean integrating pollution prevention into public policy : the case of professional wet cleaning /

Sinsheimer, Peter. January 2009 (has links)
Thesis (Ph. D.)--UCLA, 2009. / Vita. Description based on print version record. Includes bibliographical references (leaves 642-654).
136

Studies of solid carbon dioxide in interstellar ice analogs subject to thermal processing

White, Douglas W. January 2010 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2010. / Title from PDF t.p. (viewed July 20, 2010). Additional advisors: Mian M. Abbas, Renato P. Camata, Sergey B. Mirov, Thomas M. Orlando. Includes bibliographical references (p. 111-117).
137

The effectiveness of myofascial deep dry needling versus superficial dry needling in the treatment of Trapezius Myofascial Pain Syndrome

Glanz, Kelly 07 June 2012 (has links)
M.Tech. / Purpose: The purpose of this study is to investigate whether needling active trigger points in the upper fibres of the trapezius muscle, using myofascial deep dry needling versus superficial dry needling is effective in the treatment of Trapezius Myofascial Pain Syndrome. Method: Forty participants underwent a general screening to determine whether they have active myofascial trigger points in the upper fibres of the Trapezius muscle. The general screening was done by using a pincer grip technique to find the active trigger point within the trapezius. If the pincer grip revealed that there were active trigger points, the participant was suitable for this study. Each filled in a neck disability index and a pain rating scale, with algometer readings taken Pre and Post-treatment on visit 1 to visit 4. Algometer readings were taken at the active trigger point Pre and Post-treatment (subjective data). Each participant received either myofascial deep dry needling or superficial dry needling to the active trigger point. After the two week trial, the participants had to fill out a neck disability index and a pain rating scale for a second time in order to objectively measure the participants pain. Results: The results were interpreted by Statkon at the University of Johannesburg. The data was analysed using the Mann Whitney test and the Friedman test. According to the tests, both groups improved significantly in both the objective and subjective measurements over the four visits. Overall, the mean values for both the myofascial deep dry needling group and the superficial dry needling group were P = 0.001. The superficial dry needling group showed a further increase over a short term period in the objective and subjective measurements over each visit. Conclusion: Based on the results of this study, it can be concluded that both myofascial deep dry needling and superficial dry needling is effective and can be used in the treatment of Trapezius Myofascial Pain Syndrome. This study further indicated that superficial dry needling was shown to be a significantly effective treatment short term when compared to that of myofascial deep dry needling of active trigger points in the upper fibres of the Trapezius muscle
138

Spatial and Temporal Variability of Glacier Melt in the McMurdo Dry Valleys, Antarctica

Hoffman, Matthew James 01 January 2011 (has links)
In the McMurdo Dry Valleys, Victoria Land, East Antarctica, melting of glacial ice is the primary source of water to streams, lakes, and associated ecosystems. To better understand meltwater production, three hypotheses are tested: 1) that small changes in the surface energy balance on these glaciers will result in large changes in melt, 2) that subsurface melt does not contribute significantly to runoff, and 3) that melt from 25-m high terminal cliffs is the dominant source of baseflow during cold periods. These hypotheses were investigated using a surface energy balance model applied to the glaciers of Taylor Valley using 14 years of meteorological data and calibrated to ablation measurements. Inclusion of transmission of solar radiation into the ice through a source term in a one-dimensional heat transfer equation was necessary to accurately model summer ablation and ice temperatures. Results showed good correspondence between calculated and measured ablation and ice temperatures over the 14 years using both daily and hourly time steps, but an hourly time step allowed resolution of short duration melt events and melt within the upper 15 cm of the ice. Resolution of short duration melt events was not important for properly resolving seasonal ablation totals. Across the smooth surfaces of the glaciers, ablation was dominated by sublimation and melting was rare. Above freezing air temperatures did not necessarily result in melt, and low wind speed was important for melt initiation. According to the model, subsurface melt between 5 and 15 cm depth was extensive and lasted for up to six weeks in some summers. The model was better able to predict ablation if some subsurface melt was assumed to drain, lowering ice density, consistent with observations of a low density weathering crust that forms over the course of the summer on Dry Valley glaciers. In extreme summers, drainage of subsurface melt may have contributed up to half of the observed surface lowering through reduction of ice density and possibly through collapse of highly weathered ice. When applied spatially, the model successfully predicted proglacial streamflow at seasonal and daily time scales. This was despite omitting a routing scheme, and instead assuming that all melt generated exits the glacier on the same day, suggesting refreezing is not substantial. Including subsurface melt as runoff improved predictions of runoff volume and timing, particularly for the recession of large flood peaks. Because overland flow was rarely observed over much of these glaciers, these model results suggest that runoff may be predominantly transported beneath the surface in a partially melted permeable layer of weathered ice. According to the model, topographic basins, particularly the low albedo basin floors, played a prominent role in runoff production. Smooth glacier surfaces exhibited low melt rates, but were important during high melt conditions due to their large surface area. Estimated runoff contributions from cliffs and cryoconite holes was somewhat smaller than suggested in previous studies. Spatial and temporal variability in albedo due to snow and debris played a dominant role in flow variations between streams and seasons. In general, the model supported the existing assumption that snowmelt is insignificant, but in extreme melt years snowmelt in the accumulation area may contribute significantly to runoff in some locations.
139

Tear Lipid Layer Thickness and Symptoms in Patients with Dry Eye Disease following the use of Emollient versus Non-Emollient Artificial Tears

Weisenberger, Kimberly R. 08 October 2020 (has links)
No description available.
140

Transient vibrations from dry clutch operation in heavy-duty truck powertrains : Modelling, simulation and validation

Sjöstrand, Jakob January 2021 (has links)
For internal combustion engines used in heavy-duty vehicles, increased engine efficiency and consequently reduced CO2 emissions can be obtained if the engine speed can be kept within an optimal speed range. This requires swift and frequent gear shifts where the dry friction clutch is utilized. Enhanced dry clutch simulation models and a better understanding of the involved phenomena can assist the development towards swifter gear shifts and help reduce CO2 emissions. The work presented in this thesis focuses on the modelling of dry clutch systems for heavy-duty applications and their effect on the torsional response of the driveline during transient events such as clutch engagement and disengagement. During these events it is primarily the first vibration mode of the driveline that is active and consequently it is possible to greatly reduce theof degrees of freedom (DOFs) of the powertrain model and still capture the relevant dynamics of the powertrain. The reduced set of differential equationsdescribe the torsional motion of the powertrain and the equations of motion are solved numerically in the time-domain. From a mathematical point ofview, the equations of motion turn "stiff" when the clutch is locked. This issue is resolved by utilizing numerical solution techniques suitable for stiff differential equations. In the simulations it was observed that no engine torque fluctuations were transferred through the slipping clutch. Consequently the response of the driveline is purely modal during sliding. If the gradient of the coefficient of friction is negative the modal response is possibly unstable with exponentially growing vibration amplitudes as an effect. Moreover, the way in which the clamp load evolves during clutch engagement is found to severely effect the excitation of transient vibrations during clutch synchronization. It can be shown that reducing the gradient of the evolving clamp load at the onset of sliding will reduce the amplitude of the friction induced vibrations. Reducing the torsional vibration amplitudes will help avoid the jerky motion of the vehicle during launch and increase comfort for driver and passengers. / Reduced transmission vibrations - reduced energy consumption and environmental impacts together with an increased competitiveness. Swedish Energy Agency (project No. 42100-1)

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